Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 1 | // Copyright 2019 The Pigweed Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| 4 | // use this file except in compliance with the License. You may obtain a copy of |
| 5 | // the License at |
| 6 | // |
| 7 | // https://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| 11 | // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| 12 | // License for the specific language governing permissions and limitations under |
| 13 | // the License. |
| 14 | |
| 15 | #include <cstdint> |
Wyatt Hepler | e2cbadf | 2020-06-22 11:21:45 -0700 | [diff] [blame] | 16 | #include <span> |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 17 | #include <type_traits> |
| 18 | |
| 19 | #include "gtest/gtest.h" |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 20 | #include "pw_cpu_exception/entry.h" |
| 21 | #include "pw_cpu_exception/handler.h" |
| 22 | #include "pw_cpu_exception/support.h" |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 23 | #include "pw_cpu_exception_cortex_m/cpu_state.h" |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 24 | |
| 25 | namespace pw::cpu_exception { |
| 26 | namespace { |
| 27 | |
| 28 | // CMSIS/Cortex-M/ARMv7 related constants. |
| 29 | // These values are from the ARMv7-M Architecture Reference Manual DDI 0403E.b. |
| 30 | // https://static.docs.arm.com/ddi0403/e/DDI0403E_B_armv7m_arm.pdf |
| 31 | |
| 32 | // Exception ISR number. (ARMv7-M Section B1.5.2) |
| 33 | constexpr uint32_t kHardFaultIsrNum = 0x3u; |
| 34 | constexpr uint32_t kMemFaultIsrNum = 0x4u; |
| 35 | constexpr uint32_t kBusFaultIsrNum = 0x5u; |
| 36 | constexpr uint32_t kUsageFaultIsrNum = 0x6u; |
| 37 | |
| 38 | // Masks for individual bits of HFSR. (ARMv7-M Section B3.2.16) |
| 39 | constexpr uint32_t kForcedHardfaultMask = 0x1u << 30; |
| 40 | |
| 41 | // Masks for individual bits of CFSR. (ARMv7-M Section B3.2.15) |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 42 | constexpr uint32_t kUsageFaultStart = 0x1u << 16; |
| 43 | constexpr uint32_t kUnalignedFaultMask = kUsageFaultStart << 8; |
| 44 | constexpr uint32_t kDivByZeroFaultMask = kUsageFaultStart << 9; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 45 | |
| 46 | // CCR flags. (ARMv7-M Section B3.2.8) |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 47 | constexpr uint32_t kUnalignedTrapEnableMask = 0x1u << 3; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 48 | constexpr uint32_t kDivByZeroTrapEnableMask = 0x1u << 4; |
| 49 | |
| 50 | // Masks for individual bits of SHCSR. (ARMv7-M Section B3.2.13) |
| 51 | constexpr uint32_t kMemFaultEnableMask = 0x1 << 16; |
| 52 | constexpr uint32_t kBusFaultEnableMask = 0x1 << 17; |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 53 | constexpr uint32_t kUsageFaultEnableMask = 0x1 << 18; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 54 | |
| 55 | // Bit masks for an exception return value. (ARMv7-M Section B1.5.8) |
| 56 | constexpr uint32_t kExcReturnBasicFrameMask = (0x1u << 4); |
| 57 | |
| 58 | // CPCAR mask that enables FPU. (ARMv7-M Section B3.2.20) |
| 59 | constexpr uint32_t kFpuEnableMask = (0xFu << 20); |
| 60 | |
| 61 | // Memory mapped registers. (ARMv7-M Section B3.2.2, Table B3-4) |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 62 | volatile uint32_t& cortex_m_vtor = |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 63 | *reinterpret_cast<volatile uint32_t*>(0xE000ED08u); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 64 | volatile uint32_t& cortex_m_ccr = |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 65 | *reinterpret_cast<volatile uint32_t*>(0xE000ED14u); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 66 | volatile uint32_t& cortex_m_shcsr = |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 67 | *reinterpret_cast<volatile uint32_t*>(0xE000ED24u); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 68 | volatile uint32_t& cortex_m_cfsr = |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 69 | *reinterpret_cast<volatile uint32_t*>(0xE000ED28u); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 70 | volatile uint32_t& cortex_m_hfsr = |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 71 | *reinterpret_cast<volatile uint32_t*>(0xE000ED2Cu); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 72 | volatile uint32_t& cortex_m_cpacr = |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 73 | *reinterpret_cast<volatile uint32_t*>(0xE000ED88u); |
| 74 | |
| 75 | // Begin a critical section that must not be interrupted. |
| 76 | // This function disables interrupts to prevent any sort of context switch until |
| 77 | // the critical section ends. This is done by setting PRIMASK to 1 using the cps |
| 78 | // instruction. |
| 79 | // |
| 80 | // Returns the state of PRIMASK before it was disabled. |
| 81 | inline uint32_t BeginCriticalSection() { |
| 82 | uint32_t previous_state; |
| 83 | asm volatile( |
| 84 | " mrs %[previous_state], primask \n" |
| 85 | " cpsid i \n" |
| 86 | // clang-format off |
| 87 | : /*output=*/[previous_state]"=r"(previous_state) |
| 88 | : /*input=*/ |
| 89 | : /*clobbers=*/"memory" |
| 90 | // clang-format on |
| 91 | ); |
| 92 | return previous_state; |
| 93 | } |
| 94 | |
| 95 | // Ends a critical section. |
| 96 | // Restore previous previous state produced by BeginCriticalSection(). |
| 97 | // Note: This does not always re-enable interrupts. |
| 98 | inline void EndCriticalSection(uint32_t previous_state) { |
| 99 | asm volatile( |
| 100 | // clang-format off |
| 101 | "msr primask, %0" |
| 102 | : /*output=*/ |
| 103 | : /*input=*/"r"(previous_state) |
| 104 | : /*clobbers=*/"memory" |
| 105 | // clang-format on |
| 106 | ); |
| 107 | } |
| 108 | |
| 109 | void EnableFpu() { |
| 110 | #if defined(PW_ARMV7M_ENABLE_FPU) && PW_ARMV7M_ENABLE_FPU == 1 |
| 111 | // TODO(pwbug/17): Replace when Pigweed config system is added. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 112 | cortex_m_cpacr |= kFpuEnableMask; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 113 | #endif // defined(PW_ARMV7M_ENABLE_FPU) && PW_ARMV7M_ENABLE_FPU == 1 |
| 114 | } |
| 115 | |
| 116 | void DisableFpu() { |
| 117 | #if defined(PW_ARMV7M_ENABLE_FPU) && PW_ARMV7M_ENABLE_FPU == 1 |
| 118 | // TODO(pwbug/17): Replace when Pigweed config system is added. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 119 | cortex_m_cpacr &= ~kFpuEnableMask; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 120 | #endif // defined(PW_ARMV7M_ENABLE_FPU) && PW_ARMV7M_ENABLE_FPU == 1 |
| 121 | } |
| 122 | |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 123 | // Counter that is incremented if the test's exception handler correctly handles |
| 124 | // a triggered exception. |
| 125 | size_t exceptions_handled = 0; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 126 | |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 127 | // Global variable that triggers a single nested fault on a fault. |
| 128 | bool trigger_nested_fault = false; |
| 129 | |
| 130 | // Allow up to kMaxFaultDepth faults before determining the device is |
| 131 | // unrecoverable. |
| 132 | constexpr size_t kMaxFaultDepth = 2; |
| 133 | |
| 134 | // Variable to prevent more than kMaxFaultDepth nested crashes. |
| 135 | size_t current_fault_depth = 0; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 136 | |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 137 | // Faulting pw_cpu_exception_State is copied here so values can be validated |
| 138 | // after exiting exception handler. |
| 139 | pw_cpu_exception_State captured_states[kMaxFaultDepth] = {}; |
| 140 | pw_cpu_exception_State& captured_state = captured_states[0]; |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 141 | |
Wyatt Hepler | e2cbadf | 2020-06-22 11:21:45 -0700 | [diff] [blame] | 142 | // Flag used to check if the contents of std::span matches the captured state. |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 143 | bool span_matches = false; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 144 | |
| 145 | // Variable to be manipulated by function that uses floating |
| 146 | // point to test that exceptions push Fpu state correctly. |
| 147 | // Note: don't use double because a cortex-m4f with fpv4-sp-d16 |
| 148 | // will result in gcc generating code to use the software floating |
| 149 | // point support for double. |
| 150 | volatile float float_test_value; |
| 151 | |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 152 | // Magic pattern to help identify if the exception handler's |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 153 | // pw_cpu_exception_State pointer was pointing to captured CPU state that was |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 154 | // pushed onto the stack when the faulting context uses the VFP. Has to be |
| 155 | // computed at runtime because it uses values only available at link time. |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 156 | const float kFloatTestPattern = 12.345f * 67.89f; |
| 157 | |
| 158 | volatile float fpu_lhs_val = 12.345f; |
| 159 | volatile float fpu_rhs_val = 67.89f; |
| 160 | |
| 161 | // This macro provides a calculation that equals kFloatTestPattern. |
| 162 | #define _PW_TEST_FPU_OPERATION (fpu_lhs_val * fpu_rhs_val) |
| 163 | |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 164 | // Magic pattern to help identify if the exception handler's |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 165 | // pw_cpu_exception_State pointer was pointing to captured CPU state that was |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 166 | // pushed onto the stack. |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 167 | constexpr uint32_t kMagicPattern = 0xDEADBEEF; |
| 168 | |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 169 | // This pattern serves a purpose similar to kMagicPattern, but is used for |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 170 | // testing a nested fault to ensure both pw_cpu_exception_State objects are |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 171 | // correctly captured. |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 172 | constexpr uint32_t kNestedMagicPattern = 0x900DF00D; |
| 173 | |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 174 | // The manually captured PC won't be the exact same as the faulting PC. This is |
| 175 | // the maximum tolerated distance between the two to allow the test to pass. |
| 176 | constexpr int32_t kMaxPcDistance = 4; |
| 177 | |
| 178 | // In-memory interrupt service routine vector table. |
| 179 | using InterruptVectorTable = std::aligned_storage_t<512, 512>; |
| 180 | InterruptVectorTable ram_vector_table; |
| 181 | |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 182 | // Forward declaration of the exception handler. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 183 | void TestingExceptionHandler(pw_cpu_exception_State*); |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 184 | |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 185 | // Populate the device's registers with testable values, then trigger exception. |
| 186 | void BeginBaseFaultTest() { |
| 187 | // Make sure divide by zero causes a fault. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 188 | cortex_m_ccr |= kDivByZeroTrapEnableMask; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 189 | uint32_t magic = kMagicPattern; |
| 190 | asm volatile( |
| 191 | " mov r0, %[magic] \n" |
| 192 | " mov r1, #0 \n" |
| 193 | " mov r2, pc \n" |
| 194 | " mov r3, lr \n" |
| 195 | // This instruction divides by zero. |
| 196 | " udiv r1, r1, r1 \n" |
| 197 | // clang-format off |
| 198 | : /*output=*/ |
| 199 | : /*input=*/[magic]"r"(magic) |
| 200 | : /*clobbers=*/"r0", "r1", "r2", "r3" |
| 201 | // clang-format on |
| 202 | ); |
| 203 | |
| 204 | // Check that the stack align bit was not set. |
| 205 | EXPECT_EQ(captured_state.base.psr & kPsrExtraStackAlignBit, 0u); |
| 206 | } |
| 207 | |
| 208 | // Populate the device's registers with testable values, then trigger exception. |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 209 | void BeginNestedFaultTest() { |
| 210 | // Make sure divide by zero causes a fault. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 211 | cortex_m_ccr |= kUnalignedTrapEnableMask; |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 212 | volatile uint32_t magic = kNestedMagicPattern; |
| 213 | asm volatile( |
| 214 | " mov r0, %[magic] \n" |
| 215 | " mov r1, #0 \n" |
| 216 | " mov r2, pc \n" |
| 217 | " mov r3, lr \n" |
| 218 | // This instruction does an unaligned read. |
| 219 | " ldrh r1, [%[magic_addr], 1] \n" |
| 220 | // clang-format off |
| 221 | : /*output=*/ |
| 222 | : /*input=*/[magic]"r"(magic), [magic_addr]"r"(&magic) |
| 223 | : /*clobbers=*/"r0", "r1", "r2", "r3" |
| 224 | // clang-format on |
| 225 | ); |
| 226 | } |
| 227 | |
| 228 | // Populate the device's registers with testable values, then trigger exception. |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 229 | // This version causes stack to not be 4-byte aligned initially, testing |
| 230 | // the fault handlers correction for psp. |
| 231 | void BeginBaseFaultUnalignedStackTest() { |
| 232 | // Make sure divide by zero causes a fault. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 233 | cortex_m_ccr |= kDivByZeroTrapEnableMask; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 234 | uint32_t magic = kMagicPattern; |
| 235 | asm volatile( |
| 236 | // Push one register to cause $sp to be no longer 8-byte aligned, |
| 237 | // assuming it started 8-byte aligned as expected. |
| 238 | " push {r0} \n" |
| 239 | " mov r0, %[magic] \n" |
| 240 | " mov r1, #0 \n" |
| 241 | " mov r2, pc \n" |
| 242 | " mov r3, lr \n" |
| 243 | // This instruction divides by zero. Our fault handler should |
| 244 | // ultimately advance the pc to the pop instruction. |
| 245 | " udiv r1, r1, r1 \n" |
| 246 | " pop {r0} \n" |
| 247 | // clang-format off |
| 248 | : /*output=*/ |
| 249 | : /*input=*/[magic]"r"(magic) |
| 250 | : /*clobbers=*/"r0", "r1", "r2", "r3" |
| 251 | // clang-format on |
| 252 | ); |
| 253 | |
| 254 | // Check that the stack align bit was set. |
| 255 | EXPECT_EQ(captured_state.base.psr & kPsrExtraStackAlignBit, |
| 256 | kPsrExtraStackAlignBit); |
| 257 | } |
| 258 | |
| 259 | // Populate some of the extended set of captured registers, then trigger |
| 260 | // exception. |
| 261 | void BeginExtendedFaultTest() { |
| 262 | // Make sure divide by zero causes a fault. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 263 | cortex_m_ccr |= kDivByZeroTrapEnableMask; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 264 | uint32_t magic = kMagicPattern; |
| 265 | volatile uint32_t local_msp = 0; |
| 266 | volatile uint32_t local_psp = 0; |
| 267 | asm volatile( |
| 268 | " mov r4, %[magic] \n" |
| 269 | " mov r5, #0 \n" |
| 270 | " mov r11, %[magic] \n" |
| 271 | " mrs %[local_msp], msp \n" |
| 272 | " mrs %[local_psp], psp \n" |
| 273 | // This instruction divides by zero. |
| 274 | " udiv r5, r5, r5 \n" |
| 275 | // clang-format off |
| 276 | : /*output=*/[local_msp]"=r"(local_msp), [local_psp]"=r"(local_psp) |
| 277 | : /*input=*/[magic]"r"(magic) |
Armando Montanez | 1ee925c | 2020-06-29 13:15:28 -0700 | [diff] [blame] | 278 | : /*clobbers=*/"r0", "r4", "r5", "r11", "memory" |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 279 | // clang-format on |
| 280 | ); |
| 281 | |
| 282 | // Check that the stack align bit was not set. |
| 283 | EXPECT_EQ(captured_state.base.psr & kPsrExtraStackAlignBit, 0u); |
| 284 | |
| 285 | // Check that the captured stack pointers matched the ones in the context of |
| 286 | // the fault. |
| 287 | EXPECT_EQ(static_cast<uint32_t>(captured_state.extended.msp), local_msp); |
| 288 | EXPECT_EQ(static_cast<uint32_t>(captured_state.extended.psp), local_psp); |
| 289 | } |
| 290 | |
| 291 | // Populate some of the extended set of captured registers, then trigger |
| 292 | // exception. |
| 293 | // This version causes stack to not be 4-byte aligned initially, testing |
| 294 | // the fault handlers correction for psp. |
| 295 | void BeginExtendedFaultUnalignedStackTest() { |
| 296 | // Make sure divide by zero causes a fault. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 297 | cortex_m_ccr |= kDivByZeroTrapEnableMask; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 298 | uint32_t magic = kMagicPattern; |
| 299 | volatile uint32_t local_msp = 0; |
| 300 | volatile uint32_t local_psp = 0; |
| 301 | asm volatile( |
| 302 | // Push one register to cause $sp to be no longer 8-byte aligned, |
| 303 | // assuming it started 8-byte aligned as expected. |
| 304 | " push {r0} \n" |
| 305 | " mov r4, %[magic] \n" |
| 306 | " mov r5, #0 \n" |
| 307 | " mov r11, %[magic] \n" |
| 308 | " mrs %[local_msp], msp \n" |
| 309 | " mrs %[local_psp], psp \n" |
| 310 | // This instruction divides by zero. Our fault handler should |
| 311 | // ultimately advance the pc to the pop instruction. |
| 312 | " udiv r5, r5, r5 \n" |
| 313 | " pop {r0} \n" |
| 314 | // clang-format off |
| 315 | : /*output=*/[local_msp]"=r"(local_msp), [local_psp]"=r"(local_psp) |
| 316 | : /*input=*/[magic]"r"(magic) |
Armando Montanez | 1ee925c | 2020-06-29 13:15:28 -0700 | [diff] [blame] | 317 | : /*clobbers=*/"r0", "r4", "r5", "r11", "memory" |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 318 | // clang-format on |
| 319 | ); |
| 320 | |
| 321 | // Check that the stack align bit was set. |
| 322 | EXPECT_EQ(captured_state.base.psr & kPsrExtraStackAlignBit, |
| 323 | kPsrExtraStackAlignBit); |
| 324 | |
| 325 | // Check that the captured stack pointers matched the ones in the context of |
| 326 | // the fault. |
| 327 | EXPECT_EQ(static_cast<uint32_t>(captured_state.extended.msp), local_msp); |
| 328 | EXPECT_EQ(static_cast<uint32_t>(captured_state.extended.psp), local_psp); |
| 329 | } |
| 330 | |
| 331 | void InstallVectorTableEntries() { |
| 332 | uint32_t prev_state = BeginCriticalSection(); |
| 333 | // If vector table is installed already, this is done. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 334 | if (cortex_m_vtor == reinterpret_cast<uint32_t>(&ram_vector_table)) { |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 335 | EndCriticalSection(prev_state); |
| 336 | return; |
| 337 | } |
| 338 | // Copy table to new location since it's not guaranteed that we can write to |
| 339 | // the original one. |
| 340 | std::memcpy(&ram_vector_table, |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 341 | reinterpret_cast<uint32_t*>(cortex_m_vtor), |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 342 | sizeof(ram_vector_table)); |
| 343 | |
| 344 | // Override exception handling vector table entries. |
| 345 | uint32_t* exception_entry_addr = |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 346 | reinterpret_cast<uint32_t*>(pw_cpu_exception_Entry); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 347 | uint32_t** interrupts = reinterpret_cast<uint32_t**>(&ram_vector_table); |
| 348 | interrupts[kHardFaultIsrNum] = exception_entry_addr; |
| 349 | interrupts[kMemFaultIsrNum] = exception_entry_addr; |
| 350 | interrupts[kBusFaultIsrNum] = exception_entry_addr; |
| 351 | interrupts[kUsageFaultIsrNum] = exception_entry_addr; |
| 352 | |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 353 | // Update Vector Table Offset Register (VTOR) to point to new vector table. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 354 | cortex_m_vtor = reinterpret_cast<uint32_t>(&ram_vector_table); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 355 | EndCriticalSection(prev_state); |
| 356 | } |
| 357 | |
| 358 | void EnableAllFaultHandlers() { |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 359 | cortex_m_shcsr |= |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 360 | kMemFaultEnableMask | kBusFaultEnableMask | kUsageFaultEnableMask; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 361 | } |
| 362 | |
| 363 | void Setup(bool use_fpu) { |
| 364 | if (use_fpu) { |
| 365 | EnableFpu(); |
| 366 | } else { |
| 367 | DisableFpu(); |
| 368 | } |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 369 | pw_cpu_exception_SetHandler(TestingExceptionHandler); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 370 | EnableAllFaultHandlers(); |
| 371 | InstallVectorTableEntries(); |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 372 | exceptions_handled = 0; |
| 373 | current_fault_depth = 0; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 374 | captured_state = {}; |
| 375 | float_test_value = 0.0f; |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 376 | trigger_nested_fault = false; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 377 | } |
| 378 | |
| 379 | TEST(FaultEntry, BasicFault) { |
| 380 | Setup(/*use_fpu=*/false); |
| 381 | BeginBaseFaultTest(); |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 382 | ASSERT_EQ(exceptions_handled, 1u); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 383 | // captured_state values must be cast since they're in a packed struct. |
| 384 | EXPECT_EQ(static_cast<uint32_t>(captured_state.base.r0), kMagicPattern); |
| 385 | EXPECT_EQ(static_cast<uint32_t>(captured_state.base.r1), 0u); |
| 386 | // PC is manually saved in r2 before the exception occurs (where PC is also |
| 387 | // stored). Ensure these numbers are within a reasonable distance. |
| 388 | int32_t captured_pc_distance = |
| 389 | captured_state.base.pc - captured_state.base.r2; |
| 390 | EXPECT_LT(captured_pc_distance, kMaxPcDistance); |
| 391 | EXPECT_EQ(static_cast<uint32_t>(captured_state.base.r3), |
| 392 | static_cast<uint32_t>(captured_state.base.lr)); |
| 393 | } |
| 394 | |
| 395 | TEST(FaultEntry, BasicUnalignedStackFault) { |
| 396 | Setup(/*use_fpu=*/false); |
| 397 | BeginBaseFaultUnalignedStackTest(); |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 398 | ASSERT_EQ(exceptions_handled, 1u); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 399 | // captured_state values must be cast since they're in a packed struct. |
| 400 | EXPECT_EQ(static_cast<uint32_t>(captured_state.base.r0), kMagicPattern); |
| 401 | EXPECT_EQ(static_cast<uint32_t>(captured_state.base.r1), 0u); |
| 402 | // PC is manually saved in r2 before the exception occurs (where PC is also |
| 403 | // stored). Ensure these numbers are within a reasonable distance. |
| 404 | int32_t captured_pc_distance = |
| 405 | captured_state.base.pc - captured_state.base.r2; |
| 406 | EXPECT_LT(captured_pc_distance, kMaxPcDistance); |
| 407 | EXPECT_EQ(static_cast<uint32_t>(captured_state.base.r3), |
| 408 | static_cast<uint32_t>(captured_state.base.lr)); |
| 409 | } |
| 410 | |
| 411 | TEST(FaultEntry, ExtendedFault) { |
| 412 | Setup(/*use_fpu=*/false); |
| 413 | BeginExtendedFaultTest(); |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 414 | ASSERT_EQ(exceptions_handled, 1u); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 415 | ASSERT_TRUE(span_matches); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 416 | const CortexMExtraRegisters& extended_registers = captured_state.extended; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 417 | // captured_state values must be cast since they're in a packed struct. |
| 418 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r4), kMagicPattern); |
| 419 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r5), 0u); |
| 420 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r11), kMagicPattern); |
| 421 | |
| 422 | // Check expected values for this crash. |
| 423 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.cfsr), |
| 424 | static_cast<uint32_t>(kDivByZeroFaultMask)); |
| 425 | EXPECT_EQ((extended_registers.icsr & 0x1FFu), kUsageFaultIsrNum); |
| 426 | } |
| 427 | |
| 428 | TEST(FaultEntry, ExtendedUnalignedStackFault) { |
| 429 | Setup(/*use_fpu=*/false); |
| 430 | BeginExtendedFaultUnalignedStackTest(); |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 431 | ASSERT_EQ(exceptions_handled, 1u); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 432 | ASSERT_TRUE(span_matches); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 433 | const CortexMExtraRegisters& extended_registers = captured_state.extended; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 434 | // captured_state values must be cast since they're in a packed struct. |
| 435 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r4), kMagicPattern); |
| 436 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r5), 0u); |
| 437 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r11), kMagicPattern); |
| 438 | |
| 439 | // Check expected values for this crash. |
| 440 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.cfsr), |
| 441 | static_cast<uint32_t>(kDivByZeroFaultMask)); |
| 442 | EXPECT_EQ((extended_registers.icsr & 0x1FFu), kUsageFaultIsrNum); |
| 443 | } |
| 444 | |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 445 | TEST(FaultEntry, NestedFault) { |
| 446 | // Due to the way nesting is handled, captured_states[0] is the nested fault |
| 447 | // since that fault must be handled *FIRST*. After that fault is handled, the |
| 448 | // original fault can be correctly handled afterwards (captured into |
| 449 | // captured_states[1]). |
| 450 | |
| 451 | Setup(/*use_fpu=*/false); |
| 452 | trigger_nested_fault = true; |
| 453 | BeginBaseFaultTest(); |
| 454 | ASSERT_EQ(exceptions_handled, 2u); |
| 455 | |
| 456 | // captured_state values must be cast since they're in a packed struct. |
| 457 | EXPECT_EQ(static_cast<uint32_t>(captured_states[1].base.r0), kMagicPattern); |
| 458 | EXPECT_EQ(static_cast<uint32_t>(captured_states[1].base.r1), 0u); |
| 459 | // PC is manually saved in r2 before the exception occurs (where PC is also |
| 460 | // stored). Ensure these numbers are within a reasonable distance. |
| 461 | int32_t captured_pc_distance = |
| 462 | captured_states[1].base.pc - captured_states[1].base.r2; |
| 463 | EXPECT_LT(captured_pc_distance, kMaxPcDistance); |
| 464 | EXPECT_EQ(static_cast<uint32_t>(captured_states[1].base.r3), |
| 465 | static_cast<uint32_t>(captured_states[1].base.lr)); |
| 466 | |
| 467 | // NESTED STATE |
| 468 | // captured_state values must be cast since they're in a packed struct. |
| 469 | EXPECT_EQ(static_cast<uint32_t>(captured_states[0].base.r0), |
| 470 | kNestedMagicPattern); |
| 471 | EXPECT_EQ(static_cast<uint32_t>(captured_states[0].base.r1), 0u); |
| 472 | // PC is manually saved in r2 before the exception occurs (where PC is also |
| 473 | // stored). Ensure these numbers are within a reasonable distance. |
| 474 | captured_pc_distance = |
| 475 | captured_states[0].base.pc - captured_states[0].base.r2; |
| 476 | EXPECT_LT(captured_pc_distance, kMaxPcDistance); |
| 477 | EXPECT_EQ(static_cast<uint32_t>(captured_states[0].base.r3), |
| 478 | static_cast<uint32_t>(captured_states[0].base.lr)); |
| 479 | } |
| 480 | |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 481 | // TODO(pwbug/17): Replace when Pigweed config system is added. |
| 482 | // Disable tests that rely on hardware FPU if this module wasn't built with |
| 483 | // hardware FPU support. |
| 484 | #if defined(PW_ARMV7M_ENABLE_FPU) && PW_ARMV7M_ENABLE_FPU == 1 |
| 485 | |
| 486 | // Populate some of the extended set of captured registers, then trigger |
| 487 | // exception. This function uses floating point to validate float context |
| 488 | // is pushed correctly. |
| 489 | void BeginExtendedFaultFloatTest() { |
| 490 | float_test_value = _PW_TEST_FPU_OPERATION; |
| 491 | BeginExtendedFaultTest(); |
| 492 | } |
| 493 | |
| 494 | // Populate some of the extended set of captured registers, then trigger |
| 495 | // exception. |
| 496 | // This version causes stack to not be 4-byte aligned initially, testing |
| 497 | // the fault handlers correction for psp. |
| 498 | // This function uses floating point to validate float context |
| 499 | // is pushed correctly. |
| 500 | void BeginExtendedFaultUnalignedStackFloatTest() { |
| 501 | float_test_value = _PW_TEST_FPU_OPERATION; |
| 502 | BeginExtendedFaultUnalignedStackTest(); |
| 503 | } |
| 504 | |
| 505 | TEST(FaultEntry, FloatFault) { |
| 506 | Setup(/*use_fpu=*/true); |
| 507 | BeginExtendedFaultFloatTest(); |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 508 | ASSERT_EQ(exceptions_handled, 1u); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 509 | const CortexMExtraRegisters& extended_registers = captured_state.extended; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 510 | // captured_state values must be cast since they're in a packed struct. |
| 511 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r4), kMagicPattern); |
| 512 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r5), 0u); |
| 513 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r11), kMagicPattern); |
| 514 | |
| 515 | // Check expected values for this crash. |
| 516 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.cfsr), |
| 517 | static_cast<uint32_t>(kDivByZeroFaultMask)); |
| 518 | EXPECT_EQ((extended_registers.icsr & 0x1FFu), kUsageFaultIsrNum); |
| 519 | |
| 520 | // Check fpu state was pushed during exception |
| 521 | EXPECT_FALSE(extended_registers.exc_return & kExcReturnBasicFrameMask); |
| 522 | |
| 523 | // Check float_test_value is correct |
| 524 | EXPECT_EQ(float_test_value, kFloatTestPattern); |
| 525 | } |
| 526 | |
| 527 | TEST(FaultEntry, FloatUnalignedStackFault) { |
| 528 | Setup(/*use_fpu=*/true); |
| 529 | BeginExtendedFaultUnalignedStackFloatTest(); |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 530 | ASSERT_EQ(exceptions_handled, 1u); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 531 | ASSERT_TRUE(span_matches); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 532 | const CortexMExtraRegisters& extended_registers = captured_state.extended; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 533 | // captured_state values must be cast since they're in a packed struct. |
| 534 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r4), kMagicPattern); |
| 535 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r5), 0u); |
| 536 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.r11), kMagicPattern); |
| 537 | |
| 538 | // Check expected values for this crash. |
| 539 | EXPECT_EQ(static_cast<uint32_t>(extended_registers.cfsr), |
| 540 | static_cast<uint32_t>(kDivByZeroFaultMask)); |
| 541 | EXPECT_EQ((extended_registers.icsr & 0x1FFu), kUsageFaultIsrNum); |
| 542 | |
| 543 | // Check fpu state was pushed during exception. |
| 544 | EXPECT_FALSE(extended_registers.exc_return & kExcReturnBasicFrameMask); |
| 545 | |
| 546 | // Check float_test_value is correct |
| 547 | EXPECT_EQ(float_test_value, kFloatTestPattern); |
| 548 | } |
| 549 | |
| 550 | #endif // defined(PW_ARMV7M_ENABLE_FPU) && PW_ARMV7M_ENABLE_FPU == 1 |
| 551 | |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 552 | void TestingExceptionHandler(pw_cpu_exception_State* state) { |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 553 | if (++current_fault_depth > kMaxFaultDepth) { |
| 554 | volatile bool loop = true; |
| 555 | while (loop) { |
| 556 | // Hit unexpected nested crash, prevent further nesting. |
| 557 | } |
| 558 | } |
| 559 | |
| 560 | if (trigger_nested_fault) { |
| 561 | // Disable nesting before triggering the nested fault to prevent infinite |
| 562 | // recursive crashes. |
| 563 | trigger_nested_fault = false; |
| 564 | BeginNestedFaultTest(); |
| 565 | } |
Armando Montanez | 1ee925c | 2020-06-29 13:15:28 -0700 | [diff] [blame] | 566 | // Logging may require FPU (fpu instructions in vsnprintf()), so re-enable |
| 567 | // asap. |
| 568 | EnableFpu(); |
| 569 | |
| 570 | // Disable traps. Must be disabled before EXPECT, as memcpy() can do unaligned |
| 571 | // operations. |
| 572 | cortex_m_ccr &= ~kUnalignedTrapEnableMask; |
| 573 | cortex_m_ccr &= ~kDivByZeroTrapEnableMask; |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 574 | |
| 575 | // Clear HFSR forced (nested) hard fault mask if set. This will only be |
| 576 | // set by the nested fault test. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 577 | EXPECT_EQ(state->extended.hfsr, cortex_m_hfsr); |
| 578 | if (cortex_m_hfsr & kForcedHardfaultMask) { |
| 579 | cortex_m_hfsr = kForcedHardfaultMask; |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 580 | } |
| 581 | |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 582 | if (cortex_m_cfsr & kUnalignedFaultMask) { |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 583 | // Copy captured state to check later. |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 584 | std::memcpy(&captured_states[exceptions_handled], |
| 585 | state, |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 586 | sizeof(pw_cpu_exception_State)); |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 587 | |
| 588 | // Disable unaligned read/write trapping to "handle" exception. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 589 | cortex_m_cfsr = kUnalignedFaultMask; |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 590 | exceptions_handled++; |
| 591 | return; |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 592 | } else if (cortex_m_cfsr & kDivByZeroFaultMask) { |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 593 | // Copy captured state to check later. |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 594 | std::memcpy(&captured_states[exceptions_handled], |
| 595 | state, |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 596 | sizeof(pw_cpu_exception_State)); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 597 | |
Wyatt Hepler | e2cbadf | 2020-06-22 11:21:45 -0700 | [diff] [blame] | 598 | // Ensure std::span compares to be the same. |
| 599 | std::span<const uint8_t> state_span = RawFaultingCpuState(*state); |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 600 | EXPECT_EQ(state_span.size(), sizeof(pw_cpu_exception_State)); |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 601 | if (std::memcmp(state, state_span.data(), state_span.size()) == 0) { |
| 602 | span_matches = true; |
| 603 | } else { |
| 604 | span_matches = false; |
| 605 | } |
| 606 | |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 607 | // Disable divide-by-zero trapping to "handle" exception. |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 608 | cortex_m_cfsr = kDivByZeroFaultMask; |
Armando Montanez | aec61cc | 2020-03-10 15:24:53 -0700 | [diff] [blame] | 609 | exceptions_handled++; |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 610 | return; |
| 611 | } |
| 612 | |
Armando Montanez | a9ca999 | 2021-01-26 17:06:10 -0800 | [diff] [blame] | 613 | EXPECT_EQ(state->extended.shcsr, cortex_m_shcsr); |
Armando Montanez | 4159d1e | 2020-09-10 12:08:49 -0700 | [diff] [blame] | 614 | |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 615 | // If an unexpected exception occurred, just enter an infinite loop. |
| 616 | while (true) { |
| 617 | } |
| 618 | } |
| 619 | |
Armando Montanez | 356bf97 | 2020-06-04 10:35:55 -0700 | [diff] [blame] | 620 | } // namespace |
Armando Montanez | 5104cd6 | 2019-12-10 14:36:43 -0800 | [diff] [blame] | 621 | } // namespace pw::cpu_exception |